1. Field of the Invention
The present invention relates to a gasket located between a tank opening and a cap, as well as to a tank cap with the gasket.
2. Description of the Related Art
A known tank cap is a fuel cap for an automobile, which includes a closer and a gasket of a C-shaped cross section. The closer with the gasket is rotated twice or three times and is screwed to a thread formed on an inner wall of a tank opening, so as to open and close the tank opening (JP No. 4-297328A). This prior art gasket has a large number of sealing projections on the outer circumference thereof. The sealing projections are in line contact with a seal support element of the closer and with a pipe sealing face formed in the periphery of the tank opening to give a sealing face pressure of or over a preset level against the seal support element and the pipe sealing face.
This prior art C-shaped gasket requires a large compressive force in the bending direction, that is, in the moving direction of the fuel cap in the opening or closing operation, to ensure the sealing face pressure of or over the preset level. A large rotational force is accordingly required to open or close the fuel cap. This leads to the poor operating performance.